Bug 859640 – [guru] app-accessibility/mimic1-1.3.0.1 fails to compile (lto): cmu_lex.c:49:27: error: type of cmu_lex_phone_table does not match original declaration [-Werror=lto-type-mismatch]

• Status: RESOLVED FIXED
• Product: GURU

[Description Agostino Sarubbo 2022-07-21 10:27:07 UTC]

https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: app-accessibility/mimic1-1.3.0.1 fails to compile (lto).
Discovered on: amd64 (internal ref: guru_tinderbox)

NOTE:
This machine uses lto with CFLAGS=-flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing

[Comment 1 Agostino Sarubbo 2022-07-21 10:27:10 UTC]

Created attachment 792722 [details]
build.log

build log and emerge --info

[Comment 2 Agostino Sarubbo 2022-07-26 09:08:37 UTC]

Here is a bit of explanation:

-Werror=lto-type-mismatch:
User to find possible runtime issues in packages. It likely means the package is unsafe to build & use with LTO.
For projects using the same identifier but with different types across different files, they must be fixed to be consistent across the codebase.

-Werror=odr:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO. C++ code must comply with the One Definition Rule (ODR) - see https://en.cppreference.com/w/cpp/language/definition#One_Definition_Rule.

-Werror=strict-aliasing:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO.

Workarounds:
- If upstream is friendly and still active, file a bug upstream. For emulators, codecs, games, or multimedia packages, it may be worth just applying a workaround instead, as upstreams sometimes aren't receptive to these bugs (VALID FOR ALL).
- Use the new 'filter-lto' from flag-o-matic.eclass as it's likely to be unsafe with LTO (VALID FOR lto-type-mismatch - odr).
- Fix it yourself if interested, of course (VALID FOR ALL).
- Append-flags -fno-strict-aliasing (VALID FOR strict-aliasing).
- Use memcpy() but a union is sometimes suitable too (VALID FOR strict-aliasing).
- -fstrict-aliasing is implied by -O2, so this must be addressed in some form (VALID FOR strict-aliasing).

See also: https://marc.info/?l=gentoo-dev&m=165639574126280&w=2

[Comment 3 Larry the Git Cow 2024-11-02 20:52:23 UTC]

The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/proj/guru.git/commit/?id=0589822be3601d78bad38165a9fe574e497a08f5

commit 0589822be3601d78bad38165a9fe574e497a08f5
Author:     Takuya Wakazono <[e-mail]>
AuthorDate: 2024-11-01 13:26:02 +0000
Commit:     Takuya Wakazono <[e-mail]>
CommitDate: 2024-11-01 13:26:02 +0000

    app-accessibility/mimic1: fix lto build
    
    Closes: https://bugs.gentoo.org/859640
    Signed-off-by: Takuya Wakazono <[e-mail]>

 .../mimic1/files/mimic1-1.3.0.1-lto.patch          | 41 ++++++++++++++++++++++
 app-accessibility/mimic1/mimic1-1.3.0.1-r1.ebuild  | 14 +++++---
 app-accessibility/mimic1/mimic1-9999.ebuild        | 10 +++---
 3 files changed, 54 insertions(+), 11 deletions(-)